Accession Number : AD0700043

Title :   SATELLITE SYSTEMS FOR NAVIGATION USING 24-HOUR ORBITS,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF SYSTEMS ENGINEERING OPERATIONS

Personal Author(s) : Woodford,J. B. ; Melton,W. C. ; Dutcher,R. L.

Report Date : 30 JAN 1970

Pagination or Media Count : 12

Abstract : A class of satellites for navigation is described which utilize 24-hour orbits. The factors which led to the selection of this class of systems as being of special interest are briefly reviewed. The systems utilize measurement of pseudo-range and pseudo range-rate (one-way range and range-rate with a biased clock) between four satellites and a user to develop a highly-accurate, three-dimensional position and velocity fix and a time and frequency determination. The methods by which the satellite positions are determined and the system reference coordinates are made to correspond with the geodetic grid at a set of ground station locations are described. Near-optimum satellite deployments for both regional and global coverage are given. The attainable accuracy from this class of systems is described. Principal error sources are identified, and the influence on accuracy of satellite-user geometry is shown for several interesting configurations. (Author)

Descriptors :   (*NAVIGATION SATELLITES, *SYNCHRONOUS SATELLITES), RANGE(DISTANCE), POSITION FINDING, ERRORS, VELOCITY

Subject Categories : Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE